Outcomes after major or bidirectional ABO-mismatched allogeneic hematopoietic progenitor cell transplantation after pretransplant isoagglutinin reduction with donor-type secretor plasma with or without plasma exchange.

BACKGROUND: Major ABO mismatch in hematopoietic progenitor cell transplantation (HPCT) is associated with a range of immunohematologic consequences including progenitor cell infusion (PCI)-related hemolysis, delayed red blood cell engraftment, and pure red cell aplasia (PRCA). Although pretransplant (recipient) isoagglutinin reduction may be associated with decreased immunohematologic complications in this setting, there is no consensus with respect to strategies for isoagglutinin reduction. STUDY DESIGN AND METHODS: This observational study assessed the efficacy of a standardized pretransplant isoagglutinin reduction strategy incorporating donor-type secretor plasma infusions with or without plasma exchange to prevent PCI-associated hemolysis and PRCA in major or bidirectional ABO-mismatched peripheral blood HPCT. All major or bidirectional ABO-mismatched HPCTs performed between 1999 and 2010 were identified from an institutional database. Immunohematologic outcomes were determined retrospectively by review of individual medical records.
RESULTS: In total 110 major or bidirectional ABO-mismatched HPCTs had been performed. No patient developed hemolysis after PCI. With respect to PRCA incidence, 16 patients (15%) were excluded due to early mortality and three (3%) due to incomplete data; of the remaining 91 patients, five (5%) developed PRCA. Patients with PRCA had significantly higher pretransplant isoagglutinin titers (p = 0.0001) compared to those who did not develop PRCA.
CONCLUSIONS: Use of a standardized pretransplant isoagglutinin reduction strategy including donor-type secretor plasma infusions is both safe and efficient in preventing PCI-associated hemolysis and is associated with low rates of posttransplant PRCA.